import os
import sys
from llvmlite import ir
from numba.core import types, utils, config, cgutils, errors
from numba import gdb, gdb_init, gdb_breakpoint
from numba.core.extending import overload, intrinsic
_path = os.path.dirname(__file__)
_platform = sys.platform
_unix_like = (_platform.startswith('linux') or
_platform.startswith('darwin') or
('bsd' in _platform))
def _confirm_gdb(need_ptrace_attach=True):
"""
Set need_ptrace_attach to True/False to indicate whether the ptrace attach
permission is needed for this gdb use case. Mode 0 (classic) or 1
(restricted ptrace) is required if need_ptrace_attach is True. See:
https://www.kernel.org/doc/Documentation/admin-guide/LSM/Yama.rst
for details on the modes.
"""
if not _unix_like:
msg = 'gdb support is only available on unix-like systems'
raise errors.NumbaRuntimeError(msg)
gdbloc = config.GDB_BINARY
if not (os.path.exists(gdbloc) and os.path.isfile(gdbloc)):
msg = ('Is gdb present? Location specified (%s) does not exist. The gdb'
' binary location can be set using Numba configuration, see: '
'https://numba.readthedocs.io/en/stable/reference/envvars.html' # noqa: E501
)
raise RuntimeError(msg % config.GDB_BINARY)
# Is Yama being used as a kernel security module and if so is ptrace_scope
# limited? In this case ptracing non-child processes requires special
# permission so raise an exception.
ptrace_scope_file = os.path.join(os.sep, 'proc', 'sys', 'kernel', 'yama',
'ptrace_scope')
has_ptrace_scope = os.path.exists(ptrace_scope_file)
if has_ptrace_scope:
with open(ptrace_scope_file, 'rt') as f:
value = f.readline().strip()
if need_ptrace_attach and value not in ("0", "1"):
msg = ("gdb can launch but cannot attach to the executing program"
" because ptrace permissions have been restricted at the "
"system level by the Linux security module 'Yama'.\n\n"
"Documentation for this module and the security "
"implications of making changes to its behaviour can be "
"found in the Linux Kernel documentation "
"https://www.kernel.org/doc/Documentation/admin-guide/LSM/Yama.rst" # noqa: E501
"\n\nDocumentation on how to adjust the behaviour of Yama "
"on Ubuntu Linux with regards to 'ptrace_scope' can be "
"found here "
"https://wiki.ubuntu.com/Security/Features#ptrace.")
raise RuntimeError(msg)
@overload(gdb)
def hook_gdb(*args):
_confirm_gdb()
gdbimpl = gen_gdb_impl(args, True)
def impl(*args):
gdbimpl()
return impl
@overload(gdb_init)
def hook_gdb_init(*args):
_confirm_gdb()
gdbimpl = gen_gdb_impl(args, False)
def impl(*args):
gdbimpl()
return impl
def init_gdb_codegen(cgctx, builder, signature, args,
const_args, do_break=False):
int8_t = ir.IntType(8)
int32_t = ir.IntType(32)
intp_t = ir.IntType(utils.MACHINE_BITS)
char_ptr = ir.PointerType(ir.IntType(8))
zero_i32t = int32_t(0)
mod = builder.module
pid = cgutils.alloca_once(builder, int32_t, size=1)
# 32bit pid, 11 char max + terminator
pidstr = cgutils.alloca_once(builder, int8_t, size=12)
# str consts
intfmt = cgctx.insert_const_string(mod, '%d')
gdb_str = cgctx.insert_const_string(mod, config.GDB_BINARY)
attach_str = cgctx.insert_const_string(mod, 'attach')
new_args = []
# add break point command to known location
# this command file thing is due to commands attached to a breakpoint
# requiring an interactive prompt
# https://sourceware.org/bugzilla/show_bug.cgi?id=10079
new_args.extend(['-x', os.path.join(_path, 'cmdlang.gdb')])
# issue command to continue execution from sleep function
new_args.extend(['-ex', 'c'])
# then run the user defined args if any
if any([not isinstance(x, types.StringLiteral) for x in const_args]):
raise errors.RequireLiteralValue(const_args)
new_args.extend([x.literal_value for x in const_args])
cmdlang = [cgctx.insert_const_string(mod, x) for x in new_args]
# insert getpid, getpid is always successful, call without concern!
fnty = ir.FunctionType(int32_t, tuple())
getpid = cgutils.get_or_insert_function(mod, fnty, "getpid")
# insert snprintf
# int snprintf(char *str, size_t size, const char *format, ...);
fnty = ir.FunctionType(
int32_t, (char_ptr, intp_t, char_ptr), var_arg=True)
snprintf = cgutils.get_or_insert_function(mod, fnty, "snprintf")
# insert fork
fnty = ir.FunctionType(int32_t, tuple())
fork = cgutils.get_or_insert_function(mod, fnty, "fork")
# insert execl
fnty = ir.FunctionType(int32_t, (char_ptr, char_ptr), var_arg=True)
execl = cgutils.get_or_insert_function(mod, fnty, "execl")
# insert sleep
fnty = ir.FunctionType(int32_t, (int32_t,))
sleep = cgutils.get_or_insert_function(mod, fnty, "sleep")
# insert break point
fnty = ir.FunctionType(ir.VoidType(), tuple())
breakpoint = cgutils.get_or_insert_function(mod, fnty,
"numba_gdb_breakpoint")
# do the work
parent_pid = builder.call(getpid, tuple())
builder.store(parent_pid, pid)
pidstr_ptr = builder.gep(pidstr, [zero_i32t], inbounds=True)
pid_val = builder.load(pid)
# call snprintf to write the pid into a char *
stat = builder.call(
snprintf, (pidstr_ptr, intp_t(12), intfmt, pid_val))
invalid_write = builder.icmp_signed('>', stat, int32_t(12))
with builder.if_then(invalid_write, likely=False):
msg = "Internal error: `snprintf` buffer would have overflowed."
cgctx.call_conv.return_user_exc(builder, RuntimeError, (msg,))
# fork, check pids etc
child_pid = builder.call(fork, tuple())
fork_failed = builder.icmp_signed('==', child_pid, int32_t(-1))
with builder.if_then(fork_failed, likely=False):
msg = "Internal error: `fork` failed."
cgctx.call_conv.return_user_exc(builder, RuntimeError, (msg,))
is_child = builder.icmp_signed('==', child_pid, zero_i32t)
with builder.if_else(is_child) as (then, orelse):
with then:
# is child
nullptr = ir.Constant(char_ptr, None)
gdb_str_ptr = builder.gep(
gdb_str, [zero_i32t], inbounds=True)
attach_str_ptr = builder.gep(
attach_str, [zero_i32t], inbounds=True)
cgutils.printf(
builder, "Attaching to PID: %s\n", pidstr)
buf = (
gdb_str_ptr,
gdb_str_ptr,
attach_str_ptr,
pidstr_ptr)
buf = buf + tuple(cmdlang) + (nullptr,)
builder.call(execl, buf)
with orelse:
# is parent
builder.call(sleep, (int32_t(10),))
# if breaking is desired, break now
if do_break is True:
builder.call(breakpoint, tuple())
def gen_gdb_impl(const_args, do_break):
@intrinsic
def gdb_internal(tyctx):
function_sig = types.void()
def codegen(cgctx, builder, signature, args):
init_gdb_codegen(cgctx, builder, signature, args, const_args,
do_break=do_break)
return cgctx.get_constant(types.none, None)
return function_sig, codegen
return gdb_internal
@overload(gdb_breakpoint)
def hook_gdb_breakpoint():
"""
Adds the Numba break point into the source
"""
if not sys.platform.startswith('linux'):
raise RuntimeError('gdb is only available on linux')
bp_impl = gen_bp_impl()
def impl():
bp_impl()
return impl
def gen_bp_impl():
@intrinsic
def bp_internal(tyctx):
function_sig = types.void()
def codegen(cgctx, builder, signature, args):
mod = builder.module
fnty = ir.FunctionType(ir.VoidType(), tuple())
breakpoint = cgutils.get_or_insert_function(mod, fnty,
"numba_gdb_breakpoint")
builder.call(breakpoint, tuple())
return cgctx.get_constant(types.none, None)
return function_sig, codegen
return bp_internal